[Rd] Library lib.loc Option Ignored for Dependencies

[Martin Maechler]

>>>>> Benjamin Tyner 
>>>>>     on Fri, 20 Jul 2018 19:42:09 -0400 writes:

    > Here's a trick/workaround; if lib.loc is the path to your
    > library, then prior to calling library(),

    >> environment(.libPaths)$.lib.loc <- lib.loc

Well, that is quite a "trick"  -- and potentially a pretty
dangerous one, not intended when making .libPaths a closure ....


I do think that there is a problem with R's dealing of R_LIBS
and other libPaths settings, notably when checking packages and
within that recompiling vignettes etc, where the R process
starts new versions of R via system() / system2() and then gets
to wrong .libPaths() settings,
and I personally would be very happy if we got reprex'es with
small fake packages -- possibly only easily reproducible on
unix-alikes ... so we could address this as a bug (or more than
one) to be fixed.

Notably with the 3.4.x --> 3.5.0 transition and my/our tendency
of having quite a few paths in R_LIBS / lib.loc / ... I've been
bitten by problems when the wrong version of package was taken
from the wrong library path ....

Martin


    >> ------------------------------------------------------------------------
    >> Good day,
    >> 
    >> If there's a library folder of the latest R packages and
    >> a particular package from it is loaded using the lib.loc
    >> option, the dependencies of that package are still
    >> attempted to be loaded from another folder of older
    >> packages specified by R_LIBS, which may cause errors
    >> about version requirements not being met. The
    >> documentation of the library function doesn't explain
    >> what the intended result is in such a case, but it could
    >> reasonably be expected that R would also load the
    >> dependencies from the user-specified lib.loc folder.
    >> 
    >> --------------------------------------
    >> Dario Strbenac University of Sydney Camperdown NSW 2050
    >> Australia